A touchscreen is an electronic visual display that can detect the presence and location of a touch within the display area. The term generally refers to touching the display of the device with a finger or hand. Touchscreens are common in devices such as smartphones, video game consoles, personal digital assistants, satellite navigation devices, computer monitors, and other information appliances. A touchscreen enables a user to interact directly with what is displayed, rather than indirectly with a pointer controlled by a mouse or touchpad.
Although certain touchscreens can be operated with a stylus instead of a user's finger or hand, many users prefer to operate a touchscreen directly with a finger or hand to avoid the need for carrying a stylus (which is subject to loss or breakage), and to avoid awkward motion or discomfort associated with operating an information appliance using a touchscreen.
Different touchscreen technologies embodying different methods of sensing touch are known, including resistive, surface acoustic wave, and capacitive technologies. A resistive touchscreen panel includes multiple layers, including two thin, transparent electrically-resistive layers that are separated by a thin gap. When an object (e.g., a fingertip or stylus tip) presses down on an outer surface of a resistive touchscreen panel, the transparent electrically-resistive layers contact one another locally, and a signal is detected based on position of the contact. Unfortunately, resistive touchscreens suffer from relatively poor contrast due to additional reflections from the extra layer of material placed over the screen, and such touchscreens may be cumbersome to use.
Surface acoustic wave (SAW) touchscreens use ultrasonic waves that pass over the touchscreen panel. When the panel is touched, a portion of the wave is absorbed, and the resulting change in ultrasonic waves registers the position of the touch event. Unfortunately, surface wave touchscreen panels may be easily damaged by outside elements, and surface contaminants can interfere with their operation.
A capacitive touchscreen panel consists of an insulator such as glass, coated with a transparent conductor such as indium tin oxide. As the human body is also an electrical conductor, touching the surface of the screen results in a distortion of the screen's electrostatic field, which is measurable as a change in capacitance. Such location is determined and sent to a controller for processing. One characteristic of capacitive touchscreens is that they require direct contact with an electrical conductor for operation. In cold weather, usability of devices including capacitive touchscreens may be impaired by conventional gloves which are insulating in character, although special-application gloves with a patch of electrically conductive material arranged at the fingertip for intermediate contact between a user's finger and a capacitive touchscreen have been developed.
Although special-application gloves with conductive fingertips are useful to expand the utility of capacitive touch screens, it would be desirable to expand the utility of touch screens in other contexts where a user's skin may be covered by an insulating material such an adhesive carrier and/or wound covering, or where a user lacks conductive tissue at one or more regions (e.g., over a prosthetic limb).
Adhesive bandages including a central pad area and adjacent adhesive areas are well known in the art and are popular as first aid wound dressings. Such bandages may be commercially produced using roll-based machines called converters. With reference to FIGS. 1A-1B, a conventional adhesive bandage 100 generally includes an elongated strip of polymeric or fabric backing or carrier material 110 having two ends 101, 102, having an outer surface 112, and having an inner surface 111 coated with a pressure sensitive adhesive (PSA) 120. A gauze or sponge absorbent pad 130 is secured along an outer surface 132 to a surface of the PSA 120 in a central location to serve as the wound covering material. An inner wound facing surface 131 of the pad 130 may be plastic coated or otherwise treated to prevent the pad 130 from adhering to a wound. The pad 130 includes lateral boundaries 133, 134. Pores or holes 116 may be formed in the carrier 110 for ventilation. Referring to FIG. 1C, a conventional adhesive bandage 100A (with carrier 110A, adhesive layer 120A, absorbent pad 130A, and ends 101A-101B) may include plastic coated release strips 141A, 142 placed over adhesive layer 120A with non-adhered portions 143A, 144A overlapping the absorbent pad 130A. The entire assembly may be enclosed in a sealed package (not shown) and sterilized to be ready for use. In conventional adhesive bandages, at least the absorbent pad, and in some instances also the backing material, is not sufficiently conductive to permit a user to actuate a capacitive touchscreen when the absorbent pad is placed between a user's skin and the touchscreen.
Adhesive bandages with metal-containing portions are known, but do not address the problem of permitting a user to control a capacitive touchscreen. EasyAG (a/k/a SilverLon) antimicrobial silver adhesive strips (commercially available from Argentum Medical, LLC, Chicago, Ill., USA (www.silverlon.com)) include an absorbent pad with silver material arranged on the inner surface thereof for contact with a wound. Although the silver material provides low electrical resistance in a lateral direction (i.e., approximately 5 Ohms from lateral end to lateral end, as measured with a digital multimeter), a distal surface of the absorbent pad appears to lack silver material (as visible by a white appearance) and is covered by a polymeric carrier. Various tests performed of the EasyAG (a/k/a SilverLon) antimicrobial silver adhesive strips in conjunction with an Apple iPhone® 4s confirmed that when the bandage was placed over a user's fingertip with the absorbent pad arranged between the user's finger and the capacitive screen of the phone, the absorbent pad portion prevented the user from controlling the phone.
Various commercially adhesive bandages (and aluminum foil) were tested to determine their efficacy in passing a signal from a user's finger to the capacitive touchscreen of an Apple iPhone® 4s. Results are summarized in the following Table 1.
TABLE 1Summary of Results of Testing of Conventional Bandages and FoilEasyAG (a/k/aBand-Aid ®SilverLon)Band-Aid ®Band-Aid ®SheerantimicrobialAluminumFlexibleSportComfort-silver adhesive(metal)FabricStrip ®+Flex ™stripsfoilDirect signalNoYESYESYESn/aconduction, carrier +(single(single(single(single layer oradhesivelayer orlayer orlayer ordoubled)doubled)doubled)doubled)Direct signalNoNoNoNon/aconduction, carrier +adhesive + absorbentpadLateral signalNoNoNoNon/aconduction (1 cm),carrier + adhesiveDirect signalNoNoNoNon/aconduction, adhesive +carrier + aluminum foiloverlaid over carrierLateral signalNoNoNoNon/aconduction (1 cm),adhesive + carrier +aluminum foil overlaidover carrierDirect signaln/an/an/an/aYESconduction, aluminumfoil onlyLateral signaln/an/an/an/aYESconduction (1 cm),aluminum foil only
As indicated in Table 1, certain bandages permitted a touchscreen to be controlled through carrier and adhesive portions intermediately arranged between the user's skin and the touchscreen; however, none of the tested adhesive bandages enabled a user to control a capacitive touchscreen (i) through an absorbent pad intermediately arranged between the user's skin and the touchscreen, or (ii) through a carrier and adhesive when a point of contact of the user's skin was separated about 1 centimeter laterally apart from a point of contact with the touchscreen (i.e., by attempting to actuate the touchscreen using an eraser end of a pencil, with adhesive and carrier intermediate arranged between the eraser end and the touchscreen, with the eraser end being separated about 1 centimeter apart from a portion of the adhesive and carrier adhered to the user's skin). Overlaying carrier portions of such bandages with aluminum foil did not enhance conduction sufficiently to permit a capacitive touchscreen to be controlled. In comparison, aluminum foil alone intermediately arranged between a user's skin and a capacitive touchscreen permitted the touchscreen to be controlled—whether directly or laterally separated by 1 cm.
Thermally conductive wound coverings have been developed recently. For example, U.S. Patent Application Publication No. 2013/0030341 A1 to Freer et al. published on Jan. 31, 2013 discloses medical wound covering apparatuses that are effective for treatment of tissue burns. An extremely thin layer of thermally conductive metal such as aluminum is arranged at the base of a substrate and adapted to be in direct contact with a burn wound, with an outer surface of the substrate having a heat-dissipation-enhancing topography (e.g., raised surface features) to help cool burns faster by enhancing thermal convection properties. Embodiments illustrated at FIGS. 25-29 of such U.S. publication to Freer et al. discloses use of an intermediate layer 12 including absorbent material forming a window adjacent to a peripheral border of the wound covering, and with such material being intermediately arranged between the thermally conductive metal layer and a self-adhesive carrier layer that also forming a window adjacent to a peripheral border of the wound covering. Such publication to Freer et al. discloses that the centrally arranged conductive metal layer is to be arranged to directly contact the wound of a user to provide the critical function of dissipating heat from a burn wound, without any absorbent pad arranged along a central portion of the wound covering apparatus (which would otherwise interfere with the heat dissipation function).
With respect to control of a capacitive touchscreen, similar difficulties arise when portions of a user's skin are covered with self-adhesive athletic tape (e.g., including cotton carrier material), which is insufficiently conductive to permit a user to actuate a capacitive touchscreen.
Self-adhesive athletic tape typically includes a cotton carrier with adhesive arranged on one side thereof. Such tape is commonly used to wrap joint areas (e.g., ankles, wrists, fingers, etc.) to provide added support and stability, and/or to reduce swelling (e.g., following joint injury). In certain instances, joints wrapped with athletic tape may be stiff and resist movement, particularly in cold ambient conditions.
It would be desirable to provide skin covering elements enabling a user to actuate a capacitive touchscreen through skin covering elements of various types, including skin covering elements comprising adhesives. It would also be desirable to reduce stiffness of joints or tissues wrapped with athletic tape. It would further be desirable to enable a skin covering element to communicate with at least one electrical device. Various embodiments as disclosed herein address one or more of the foregoing concerns.